The present invention relates to an airbag and an airbag apparatus provided with a gas-discharging device such as a venthole or the like that absorbs a shock by discharging gas from an inner part of a chamber of the airbag toward outside of the chamber, and more particularly, to an airbag that is partitioned into a plurality of chambers in an inner part thereof. The invention further relates to an airbag apparatus provided with the airbag.
Hitherto, it is known that a shock applied to an occupant in a motor vehicle or the like is absorbed by providing a venthole in an airbag and discharging gas from an inner part of the airbag via the venthole, when the occupant in the motor vehicle or the like hits the expanded airbag.
Japanese Unexamined Patent Application Publication No. 2000-16228 describes an airbag configured such that the venthole is covered with a lid member until gas-pressure of the inner part of the airbag reaches a predetermined pressure and when the gas-pressure exceeds the predetermined pressure, the lid member is pushed open by the gas pressure and the venthole is opened.
Further, in Japanese Unexamined Patent Application Publication No. 2000-16228, an airbag for use in a driver-side seat of a motor vehicle is described. The airbag described in Japanese Unexamined Patent Application Publication No. 2000-16228 is formed by stitching each of peripheral edge portions of two sheet members (panels) both having a round shape, and an entire airbag forms one chamber. A venthole is provided in the sheet member at a side of the airbag opposite to a side of an occupant in the motor vehicle and the lid member is provided in a manner so as to cover the venthole.
In Japanese Unexamined Patent Application Publication No. 2000-16228, when the airbag is expanded, the venthole is covered with the lid member until the gas pressure of the inner part of the airbag reaches the predetermined pressure. Because the gas is limited to be discharged from the venthole, the gas pressure of the inner part of the airbag promptly rises to become relatively high pressure and the airbag is promptly developed.
Furthermore, when the gas pressure of the inner part of the airbag exceeds the predetermined pressure, because the lid member is pushed open and the venthole is opened, the gas is discharged from the inner part of the airbag via the venthole when the occupant in the motor vehicle hits the expanded airbag. Thereby, the shock applied to the occupant in the motor vehicle is absorbed.
Accordingly, an object of the present invention is to realize a prompt development of the airbag without losing shock-absorbing characteristics, even in the airbag that is partitioned into a plurality of chambers in an inner part thereof.
Further objects and advantages of the invention will be apparent from the following description of the invention and the associated drawings.